The top two finished safely in the bunch on Monday's 156.4km stage 16, which was won by Team BMC's Jempy Drucker, with Froome still eyeing a second Grand Tour win of the season.
The Team Sky man fell to 3:37 behind his Colombian rival after being dropped in the closing stages of Sunday's stage 15, but the Brit is not giving up yet, with Friday's 37km flat time trial from Xabia to Calp.
"It's less possible than it was before but it doesn't mean I'm going to stop trying," the three-time Tour de France winner said of his Vuelta a Espana chances.
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"I'm still in second place, which obviously I'm happy about, but I am a lot further back than I was going into Sunday, so obviously that was a big blow.
"But that's cycling, things can change in the blink of an eye and I've got to keep fighting to the end. Of course I'm not just going to give up now."
The peloton returns to action on Wednesday with a 177.5km ride from Castellon to Llucena. Camins del Penyagolosa, including three categorised climbs before the final ramp up to Alto Mas de la Costa.
Should Froome win the race, he would be the first man to do the Tour-Vuelta double for 38 years.
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